In Reply: Angiographic Features of Meningiomas Predicting Extent of Preoperative Embolization

To the Editor: We thank Dr Rahman and his colleagues for their letter in response to our article.1,2 The authors thoughtfully point out the importance of further characterizing meningiomas across tumor location, vascular feeding networks, and dural attachments alongside risk factors for recurrence to guide meningioma management and prognosis. We thank the authors for drawing connections between our study and other related work with concordant findings, including that of Arima et al3, and we agree with their emphasis on identifying the region of dural attachment of the meningioma along the skull base, together with the associated arterial supply. A number of radiographic and angiographic techniques are emerging to accomplish these goals, which should arguably enter the treatment plan for all meningiomas. Studies have suggested that tumor embolization reduces surgical blood loss and total operating time through early devascularization and reduces the difficulty of resection by inducing tumor necrosis.4-6 However, these factors have historically been difficult to quantify, resulting in limited consensus regarding the efficacy of preoperative meningioma embolization.6 The paucity of strong evidence alongside the cost and risks of an additional procedure have prevented meningioma embolization from widespread adoption.7 Our recent manuscripts in Neurosurgery and Interventional Neuroradiology represent the initial efforts between our Skull Base and Cerebrovascular Neurosurgery groups at providing quantitative and qualitative insights into the devascularization of meningiomas through preoperative embolization.2,8 As Rahman and colleagues suggest, a number of important questions remain to be answered and can be addressed in follow-on clinical studies extending our current work. The optimal time interval between embolization and resection remains to be established. The importance of angiogenesis in the growth and potential treatment of meningiomas leads to a number of questions, including whether antiangiogenic agents might enhance the efficacy of tumor embolization. Interestingly, Akimoto et al9 (2023) recently demonstrated that preoperative embolization prolonged the time to recurrence of meningiomas in a propensity-matched analysis, further emphasizing the role of embolization as an important adjunct to surgery. Beyond meningioma embolization as an adjunct to surgery, there is evidence to suggest that in certain cases, embolization alone may be appropriate as a stand-alone treatment in carefully selected cases. Multiple case reports have demonstrated a volume reduction after meningioma embolization without resection, with one case report even showing complete resolution of a small asymptomatic meningioma after middle meningeal artery embolization for chronic subdural hematoma.10,11 Importantly, there is currently one ongoing single-arm clinical trial in Norway assessing the efficacy of meningioma embolization as stand-alone therapy for selected meningiomas; the trial is scheduled for primary completion in 2027.12 We agree that at least for patients who are not surgical candidates, this treatment paradigm requires further study and may lead to a revised standard of care for the treatment of meningiomas. Our forthcoming work will address the histological impact of embolization on meningiomas, as well as refined quantitative radiographic analyses of meningiomas before and after embolization. We are also investigating the extent to which effective embolization can affect surgical approaches. In some cases, there is the potential for embolization to facilitate more minimally invasive surgical approaches when embolization results in extensive devascularization. In others, there may be a role for embolization as stand-alone treatment in patients who are not candidates for open surgical resection.